With the popularity of network terminals, more and more families and enterprises now have multiple network terminals. As shown in FIG. 1, through wired or wireless local area network (LAN) devices, network terminals of different forms and having different functions and characteristics are connected into a LAN, which is connected to a wide area network (WAN) through a digital gateway and communication devices. In this networking mode, each network terminal can access the WAN to implement the services such as webpage browsing and point-to-point communication.
An IP multimedia subsystem (IMS) is a subsystem of a multimedia service network, which is introduced by the 3GPP based on a packet bearer network and the trend of the convergence of the Internet and telecommunication networks. Considering the fixed to mobile convergence (FMC), subsystems of the multimedia service network, such as the IMS, are more frequently used to provide multimedia services to mobile terminals and fixed terminals.
The bearer of the IMS is an (Internet Protocol) IP network. The IMS can provide a complete set of solutions to IP multimedia services, which satisfy the requirements for security, charging, roaming, and quality of service (QoS) of multimedia services. The prototype of the IMS can be regarded as a platform for the IP multimedia services. In addition to the mobile network, the IMS is also applicable to the fixed network. The uniform structure provided by the IMS supports various IP-based services on the packet switched network and circuit switched network, which is irrespective of the access technology.
In the IMS, a network terminal, such as user equipment (UE) is configured with a universal mobile telecommunications system integrated circuit card (UICC) and/or an IMS subscriber identity module (ISIM). The UICC and/or ISIM card or module store the information about the identity certification of service subscribers related to the authentication. When a subscriber registers with the IMS network, the subscriber sends a registration request carrying subscriber information related to the authentication. After the IMS determines that the subscriber is legal through the subscriber information related to the authentication, the IMS provides multimedia services to the subscriber. When the network terminal needs the multimedia services provided by a subsystem of the multimedia service network, such as the IMS domain, the network terminal provides a function of access authentication to the subsystem domain of the multimedia service network. The gateway, for example, the gateway in FIG. 1, only provides a function for network terminals to access the WAN, but does not provide the function of access authentication function to the IMS domain. When the subscriber certification information to the IMS is not configured on a network terminal (for example, a fixed network terminal), the network terminal cannot pass the identity certification of the IMS, and thus cannot obtain the multimedia service provided by the IMS.
The gateway supporting the UICC is provided, in which the subscriber certification information on a UE can be shared by plugging the UICC or ISIM card of the UE having the UICC and/or ISIM into the gateway. However, the card should be plugged in and pulled out frequently in this solution, so it is inconvenient to use.